Split index.html into partials

Every section of the site now has its own folder in the partials/
folder.
Re-adding index.html

Since index.html is so similar to stats.html, git thinks that
index.html was moved in the previous commit. Re-adding it here.
Major restructuring!

Restructured into src/, build/ and assets/. All scripts are now written
in coffeescript. Grunt takes care of the entire build process: just
type “grunt”.
Merge branch 'coffeefication' into develop
Refactored app.css into multiple scss files

app.css now only contains css that applies to all partials. The rest of
 the css has been put in the respective partial’s folder.
Merge branch 'scssification' into develop
Jadified the html

The app’s html is now generated from jade templates. This means that we
can split the html up into partials without angular having to fetch
partials after page load anymore (which reduced page rendering time
from ~300ms to ~200ms). Plus, jade is nice to code in.
Merge branch 'jadification' into develop
Externalised angular and normalize dependencies

angular.js and normalize.css are now loaded from a cdn. Lower
bandwidth, and bower is no longer needed.
Merge branch 'externalisation' into develop
Merge branch 'develop'